When diagnosed, most osteosarcoma patients will show no clinical evidence of distant disease, but microscopic deposits may have already formed in the lung, and it is these metastases that contribute to poor survival rates. This is why we need better ways of monitoring how osteosarcoma is progressing.
Dogs are 10 times more likely than people to develop osteosarcoma, so focusing on dogs with naturally occurring forms of the cancer could yield vital insight into our understanding of the disease and how it spreads in humans. Dogs develop the same pattern of clinical disease as people, with the tumour developing in bone and spreading to distant organs such as the lung through cells entering the bloodstream (known as circulating tumour cells or CTCs).
How will this project tackle this challenge?
Blood tests for CTCs are already being used to monitor disease progression in other cancers, and a similar approach could be adopted for osteosarcoma. Blood levels of CTC in a dog with naturally occurring osteosarcoma that has undergone the standard treatment of surgery and chemotherapy will be measured over time. These results will then be compared with clinical data on disease progression and overall survival.
This project will make use of the clinical population of dogs seen at the veterinary school for diagnosis and management of osteosarcoma. Positive results from this study will help support the use of CTC measurements to track disease and response to therapy in osteosarcoma.
What this means for people affected by sarcoma
Looking at the blood tests results of dogs being treated for osteosarcoma will help us study the connection between levels of circulating tumour cells and disease progression. This should improve our understanding of how osteosarcoma spreads, and will lead to safer and more effective treatments for osteosarcoma in both people and dogs.